Oxygen probe having ceramic-protected gas electrode

摘要

The oxygen probes are used to measure oxygen. Exhaust gases, carburisation gases and other carbon-containing gases, however, corrode the gas electrode of the probe. Quartz and corundum dust act as a sand jet in the furnaces with gas circulation. The gas electrode of the known probes is therefore gradually ground away, although other components are still serviceable for many years. The novel oxygen probe has a plurality of protective devices, all of which comprise an impermeable ceramic wall which deflects the gas flow from the electrode metal. In this way the result is achieved that soot and dust particles are kept away as a result of the centrifugal force, the electrode is only exposed to the gas flow at the point where the probe voltage is produced, and the actual metal of the electrode forms a metal matrix in a ceramic matrix and can therefore only corrode at the surface. Fortunately, the heavier molecules are corrosive and they are also deflected from the electrode.